The purpose of the Image Analysis Core will be to provide centralized image analysis services to each of the Components of the Program Project. Three types of specialized measures will be carried out: muscle fiber size and distribution in Components I, II and IV, density of immunocytochemically labeled spinal cord fiber systems and morphometric reconstruction and analysis of labeled motoneurons in Components I, III and IV. The Core Facility consists of one room (300 sq. ft.) containing two Biographics Image Analysis Workstations. Each workstation consists of a microscope with fluorescence capability and a motorized stage and controller which feeds X,Y and Z coordinates to the computer. Each computer is a 486 with 135 MB hard disk and an external optical disk storage (650 MB each) device. A digitizing tablet with mouse allows inputting of the microscope Image through a drawing tube. Each workstation is capable of morphometric analyses (including area, volume, lengths, branching, etc.), three dimensional reconstruction (line drawings, solid and transparent objects), quantitative densitometry (including quantitative autoradiography, gel density, etc.), frame grabbing (video or photographed images), and various other functions. Data can be displayed on spreadsheet format, graphed format or in color images. Output formats are color photographs or slides, or laser printed images or data. The centralized measurement of muscle fiber size and distribution, immunocytochemically labeled afferent fiber density and reconstruction of labeled cells across Components will allow standardization of results across Components, permitting comparison across paradigms and species. This will free each Component to make the more complex individual analyses proposed.